Material handling apparatus



N 1966 P. L. EHRHORN MATERIAL HANDLING APPARATUS 2 Sheets-Sheet 1 Filed June 17, 1964 w W A E V m PHILIP L. EH RHORN M%9;fi

ATTORNEY Nov. 22, 1966 p, EHRHORN 3,286,861

MATERIAL HANDLING APPARATUS Filed June 17, 1964 2 Sheets-Sheet 2 INVENTOR.

PHI LIP L. EHRHORN QTTO RN EY United States Patent 3,286,861 MATERIAL HANDLING APPARATUS Philip L. Ehrhorn, 3965 Regan Drive, San Mateo, Calif. Filed June 17, 1964, Ser. No. 375,836

8 Claims. (Cl. 214-314) This invention relates to material handling apparatus, and more particularly to tractor mounted power lift and dumping apparatus.

Tractor mounted power lift and dumping apparatus of various types are well known and may be divided into two categories when broadly considered. The first and most common of these categories is the fork lift and bucket category. This type of apparatus comprises at least one support and lifting arm and at least one cooperating dumping arm. The fork lift or bucket is hinged to the ends of the arms and the arms may be hinged together in such a way that the angle of the fork lift or bucket is controlled during the lifting operation. Dumping is accomplished by an appropriate change in the length of the dumping arm to cause the fork lift or bucket to tip and release its contents. The fork lift version is most useful in handling solid objects of varying size such as lumber, boxes, hay and brush, Whereas the bucket version is most useful in handling flowable or particulated materials such as sand, gravel, rocks or even fruit. The disadvantage of this category of apparatus is that in certain material handling operations, the loading of the fork lift or bucket for subsequent lifting and dumping is a difiicult, time consuming, or ineffective process.

In such operations it has been found desirable to use a plurality of special containers, instead of the fork lift or bucket, which containers are individually loaded and subsequently attached to the ends of the arms of the apparatus. This is the second and less common category of power lift and dumping apparatus. It is obvious that if apparatus of this category is to be useful the attachment of the container to the arms must be easily and quickly accomplished. To this end a large number of specialized and complicated mechanisms have been designed. Such mechanisms have been expensive and diflicult to install. The container used with one type of mechanism cannot be used with another type of mechanism and all have required the removal of the fork lift or bucket so that the special mechanism may be attached.

It is an object of this invention to provide a simple and inexpensive mechanism for attachment to conventional power lift and dumping apparatus to enable a variety of separable containers to be automatically engaged, retained and released.

It is another object of this invention to provide an improved combination of mechanism and container for use with conventional tractor mounted power :lift and dumping apparatus.

It is further an object of this invention to provide an improved container for use with tractor mounted power lift and dumping apparatus.

These and other objects and advantages of this invention will become more clearly apparent from the following detailed description and the attached sheets of drawings wherein:

FIGURE 1 is a side view of a representative form of tractor mounted power lift and dumping apparatus on which a device according to the preferred embodiment of this invention has been mounted. The apparatus is shown in solid lines in its lowered position with the container disengaged. The raised and dumped position of the apparatus with the container engaged is indicated in this figure in phantom;

forwardly of the tractor 12.

FIGURE 2 is a perspective view of the attachment device according to the preferred embodiment of this invention;

FIGURE 3 is a perspective view of the container according to the preferred embodiment of this invention;

FIGURE 4 is a side view of the attachment device and container according to the preferred embodiment of this invention with the container engaged and the apparatus in a raised position;

FIGURE 5 is a side view of the attachment device and container according to the preferred embodiment of this invention with the apparatus in its lowered position and immediately prior to' engagement, or subsequent to disengagement, of the container.

Referring to FIG. 1 a representative form of tractor mounted power lift and dumping apparatus 10 usable with the attachment device and container according to this invention comprises a pair of support and lifting arms 11 mounted on the tractor 12 for rotation about one of their ends. In the apparatus showna pair of vertical stanchions 13 are rigidly fixed to the frame of tractor 12 on opposite sides thereof and near the rear axle. The ends of the support and lifting arms 11 are attached, one to each stanchion 13, for rotation about an axis 14, with the free ends of the arms projecting A pair of hydraulic ram units 15 each having one end rotatably fixed to the frame of the tractor and the other end rotatably fixed to one of the support :and lifting arms 11 intermediate the axis 14 and the free end of the arm 11, supply the force required to rotate the arms about the axis 14 to raise the free ends of the arms 11.

In the apparatus shown in FIG. 1 the ends of a pair of dumping arms 16 are also attached, one to each stanchion 13, for rotation about an axis 17 spaced above the axis 14 about which the lifting arms rotate. A rigid guide member 18 is fixedly mounted ,on each lifting arm 11 at a point intermediate its end and slidably engages its associated dumping arm 16 to prevent lateralmovement of the dumping arms 16. A pair of double acting dumping rams 19 are carried one on the free end of each dumping arm 16. One end of each dumping ram 19 is rotatably fixed to the end of its associated dumping arm 16. The other end of each dumping ram 19, as well as the free ends of the lifting arms 11, are adapted to be rotatably fixed to an appropriate load bearing device 20.

According to the preferred embodiment of the invention the load bearing device 20 is a more or less conventional fork lift. comprising a pair of spaced parallel tines 21 extending rigidly at right angles. from a backboard 22. As shown, the backboard 22 normally extends vertically and the tines 21 horizontally. The backboard comprises a pair of rigid posts 23 interconnected by a pair of rigid cross-bars 24. Each of the posts 23 is mounted at its lower end on the free end ofone of the lifting arms 11 for rotation about an axis 25. The free end of each of the dumping rams 19 is also attached to one of the posts 24 for rotation about an axis 26 at a distance above the axis 25. Thus, each of the stanchions 13, with its associated lifting arm 11, dumping arm 16 and backboard post 24 forms an irregular parallelogram. Since the stanchions 13 are rigidly fixed to the frame of the tractor; 12 in a vertical position, the backboard posts 24 are also maintained in a vertical position regardless of the movement of arms ll and 16 resulting in changes in their angles with respect to stanchions 13 and posts 24 by rotation about axes 14, 17, 25 and 26. Thus, as shown in FIGURE 1, when'the lifting rams 15 are extended it will cause the lift arms 11 and dumping arms 16 to rotate about axes 14 and 17 respectively in a counter clockwise 3 1 direction. At the same time the posts ,23 will rotate in a clockwise direction with respect to the lift arms 11 and dumping arms 16 about axes 25 and 26 respectively. So long as the lengths of the lifting arms 11 and the dumping arms 16 are maintained constant the backboard 22 will be maintained in a vertical position and the tines 21 in a horizontal position. Dumping of the load bearing member is accomplished by extending the double acting dumping rams 19 as shown in phantom in FIGURE 1. The load bearing device 20 is returned to level position by reversing the. action of the dumping rams 19 to retract them. There are other types of power lift and dumping apparatus, which may be used with this invention. In one such type, for example, the dumping arms 16 are rigidly mounted on the lifting arms 11, as for example by substituting a rigid interconnection for the guide means 18. That portion of the dumping arm extending between stanchion 13 and the rigid interconnection (formerly guide ,means 18) is omitted, and leveling of the load bearing acting dumping rams 19. In all other respect the operation of this type of power lift and dumping apparatus is the same as that shown in the drawing and described above. Thus, power lift and dumping apparatus usable with this invention may take a variety of forms. For the preferred embodiment of this invention, however, it is necessary that the apparatus include at least one lifting arm and that rotation occur between the lifting arm and the load bearing member when the load bearing member is raised or lowered as will become more apparent hereinafter.

According to this invention, as is most clearly shown in FIGURES 2, 4, and 5, a container locking mechanism 30 is mounted on the load bearing device. 20. The container locking mechanism 30 comprises a locking means 31 .and an actuating means 32. According to the preferred embodiment of this invention the locking means 'is a hook like member comprising a straight shank 33 with a portion 34 extending at a right angle'from one of the shank 33 which are journaled into support posts 36. The locking means is oriented with the end of the shank 33 carrying the right angle portion 34 projecting beyond the backboard 22 in the same direction as the tines 21 project from the backboard 22.

According to the preferred embodiment of this invention the actuating means-32 of the container locking mechanism 30 comprises a simple tension spring 32 connected between cross-bar 24 on which the locking means is mounted and a point on the shank adjacent the end thereof opposite from the right angle portion 34. A rotation limit stop 37 extends between supportposts 36 to abut the bottom of shank 33, as is most clearly indicated in FIGURES 4 and 5. The limit stop 37, tension spring 32,. and locking means 31 are arranged so that when the tension spring 32 urges the locking means to rotate into contact with the limit stop 37, the shank 33 of locking means 31 is parallel with the tines 21 of the load bearing device 20. This is the locked position of the locking mechanism and it will be seen that the locking mechanism will always assume this position unless acted upon by other means.

In order to provide for the release of the locking mechanism 30 a release means is provided on the support arms 11. According to the preferred embodiment of the invention the release means comprises a cross-bar 38 extending between the support arms 11 at right angles thereto. The bar. 38 is located on the arms 11 at a position spaced rearwardly from the pivot axis, 25 by a distance approximately equal to the length of the shank 33 rearwardly from the trunnions 35. Thus, as is most clearly shown in FIGURES 4 and .5, when the load bearing device 20 is lowered the support arms 11 will rotate in clockwise direction with respect to the backboard 22 bringing the cross-bar 38 .into contact with the rearward endof the shank 33. The force exerted on the shank 33 by the cross-bar 38 as the load bearing device 20 is lowered will act in opposition to the tension spring 32 causing the locking means 31 to rotate on trunnions 35 in;a.clockwise direction away from the rotation limit stop 37 and lowering the right angle portion 34 of the locking means.

When the load bearing device 20 is raised, the support arms 11 will tend to rotate about axis 25 :in a counterclockwise direction with respect to the backboard 22. The cross-bar 38 carried by the support arms 11 will be rotated away from the shank 33 and the tension spring 32 will return the locking means to its locked position. As will be more fully described hereinafter a safety bar 39 is rigidly fixed to the backboard 22 and has a surface extending from the backboard 22 vin the same direction as thetines 21 and lying in a plane which is slightly above the end of right angle portion 34 of locking means 31 when the locking means is in its locked position; that is, rotated into abutment with stop 37.

The material handling container 40 according to this invention may be a simple box, as is best shown in FIG- URE 3, having a pair of skids 41 mounted on the bottom 45 of the box to accommodate the tines 21 of the load bearing device. In order to accommodate the locking mechanism 30 according to the invention, the end 42 of the container perpendicular to the skids 41 is made reentrant as for example by rigidly mounting a pair of corner posts 43 on the bottom 45 of the container. and placing the end 42 inwardly of the corner posts. A locking bar 44 is rigidly connected between the corner posts 43 parallel to the bottom of the container. The sides 46 of the container preferably. overlap the corner posts 43. The end of the container opposite the re-entrant end 42 is preferably left open to facilitate dumping of the container, and the top of the container is preferably left open to facilitate loading of the container 40. i

As best shown in FIGURES 1 and 5, when the container is disengaged it rests on skids 41 which support the bottom 45 of the container at a sufficient height to allow the tines 21. to be inserted thereunder when theload bearing device 20 is in its lowered position. As explained above, when the load bearing device 20 is in its lowered position the locking means 31 will be in its opened position due to the contact between cross-bar 38 and shank 33. Referring to FIGURE 5 the locking bar 44 is located at a distance above the bottom 45 of the container 40 such that when the tines 21 of the load bearing device 20 contact the bottom of the container the locking bar will just clear the free end of the right angle portion 34 of the locking means 31 in its opened position. The safety bar 39 is located on the backboard 22 at the proper distance above the tines 21 so that it will just clear the locking bar 44 when it is brought into contact with the backboard 22. Thus, in order to engage the container 40, it is only necessary to push the tines 22 under the container between the skids 41 until the locking bar 44 is brought into contact with the backboard 22. The locking bar 44 will pass over the right angle portion 34 of the locking means 31 and under the safety bar 39.

As best shown in FIGURE 4, when the loadbearing device 20 is raised the tines 21 will be brought into contact with the bottom of the container lifting it. At the same time the tension spring 32 will rotate the locking means 31 on trunnions 35 causing the right angle portion 34 of the locking means to enter the re-entrant end 42 of container 40 behind locking bar 44. The re-entrant end 42 of container 40 is thus held tightly againstbackboard 22.

As shown in phantom in FIGURE 1, the locking means will hold the container securely on the load bearing means during the dumping operation. The right angle portion 34 of the locking mechanism 30 will bear against the locking bar 44 to prevent the container 40 from sliding off the load bearing device 20. The safety bar 39 prevents the container 40 from tilting with respect to the tines 21 which would tend to allow the right angle portion 34 of the locking means to escape from behind the locking bar.

As will be apparent from the preceding description, when the load bearing device is returned to its normal position from the dumped position, and lowered to the ground, the locking means will be opened by the crossbar 38. As the load bearing means approaches its lowered position the container 40 will again come to rest on its skids 41 so that the tines 21 of the .load bearing member may be withdrawn. Thus, it will be seen that according to this invention a container may be automatically locked into place on a load bearing means simply by the action of raising the load bearing means and automatically unlocked from the load bearing means by the action of lowering the load bearing means.

Although specific details of the present invention are shown and described herein, it is to be understood that modifications may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A power liftand dumping apparatus comprising at least one support arm, a load bearing member pivotally connected to said support arm, means for moving said arm to adjust said load bearing member between raised and lowered positions, locking means comprising a shank portion pivotally connected to said load bearing member and an up-turned hook portion, means connected to said support arm and engageable with said shank portion when said load bearing member is moved to said lowered position to cause said hook portion to move downwardly, and means for moving said hook portion upwardly when said load bearing member is raised.

2. A power lift and dumping apparatus comprising at least one support arm, at least one dumping arm, a load bearing member pivotally connected to said arms, means for moving said support arm to adjust said load bearing member between raised and lowered position, locking means comprising a shank portion pivotally connected to said load bearing member and an up-turned hook portion, means connected to said support arm and engageable with said shank portion when said load bearing member is moved to said lowered position to cause said hook portion to move downwardly, means for causing said hook portion to move upwardly when said load bearing member is raised, a container adapted to be supported by said load bearing member, and means on said container engageable by said locking means as said hook portion moves upwardly.

3. The apparatus as claimed in claim 2 further comprising means for preventing said container from becoming disengaged from said locking means when said container is in an elevated position.

4. A power lift and dumping apparatus comprising at least one support arm, at least one dumping arm, a mounting structure to which said arms are pivotally attached adjacent one end of the arms, a backwall structure pivotally attached to the other end of said arms, a pair of laterally spaced tines connected to said backwall structure and forming therewith a load bearing member, a locking hook having a shank portion mounted on said load bearing member and a hook portion on the same side of said backwall as said tines, and a container having skids, a raised floor mounted on said skids whereby said tines will fit under said floor when said skids rest on a surface, and a locking bar on said container engaged by said locking hook when said container rests on said tines.

5. A power lift and dumping apparatus as claimed in claim 4 further comprising a safety bar on said back wall and overlapping said locking bar when said locking hook engages said locking bar to prevent accidental release of said container.

6. A power lift apparatus comprising at least one support arm, a load bearing member pivotally connected to said arm, means for moving said arm to adjust said load bearing member between raised and lowered positions resulting in angular movement of said load bearing member with respect to said arm, locking means on said load bearing member, and release means on the support arm for releasing said locking means automatically upon movement of said load bearing member between said raised and lowered positions, said release means being actuated by said angular movement of said load bearing member with respect to said arm.

7. A power lift apparatus as claimed in claim 6 in which said means for releasing said locking means comprises an abutment surface on said support arm.

8. A power lift and dumping apparatus comprising at least one support arm, at least one dumping arm, a mounting structure to which said arms are pivotally attached adjacent one end of the arms, a backwall structure pivotally attaehed to the other end of said arms, a pair of laterally spaced tines connected to said backwall structure and forming therewith a load bearing member, a locking hook having a shank portion pivoted to said load bearing member and a hook portion on the same side of said backwall as said tines, spring means urging said locking hook to rotate, means for adjusting said support am1 .between raised and lowered positions resulting in angular movement of said load bearing member with respect to said arm, and a cross-bar on said support arm which is brought into engagement with said shank portion of said locking hook by said angular movement when said support arm is lowered, whereby said spring means urging rotation of said locking hook is overpowered and said locking hook is caused to rotate in the opposite direction.

References Cited by the Examiner UNITED STATES PATENTS 1,249,805 12/1917 Morison et al. 214146 2,482,692 9/ 1949 Quayler et a1. 214-620 2,515,384 7/1950 Von Camop 214- X 2,582,759 1/1952 Sass 214-620 2,718,318 9/1955 Schmucker et al 214140 3,115,261 12/ 1963 Antolini 214620 FOREIGN PATENTS 764,983 1/ 1957 Great Britain.

HUGO O. SCHULZ, Primary Examiner. 

2. A POWER LIFT AND DUMPING APPARATUS COMPRISING AT LEAST ONE SUPPORT ARM, AT LEAST ONE DUMPING ARM, A LOAD BEARING MEMBER PIVOTALLY CONNECTED TO SAID ARMS, MEANS FOR MOVING SAID SUPPORT ARM TO ADJUST SAID LOAD BEARING MEMBER BETWEEN RAISED AND LOWERED POSITION, LOCKING MEANS COMPRISING A SHANK PORTION PIVOTALLY CONNECTED TO SAID LOAD BEARING MEMBER AND AN UP-TURNED HOOK PORTION, MEANS CONNECTED TO SAID SUPPORT ARM AND ENGAGEABLE WITH SAID SHANK PORTION WHEN SAID LOAD BEARING MEMBER IS MOVED TO SAID LOWERED POSITION TO CAUSE SAID HOOK PORTION TO MOVE DOWNWARDLY, MEANS FOR CAUSING SAID HOOK PORTION TO MOVE UPWARDLY WHEN SAID LOAD BEARING MEMBER IS RAISED, A CONTAINER ADAPTED TO BE SUPPORTED BY SAID LOAD BEARING MEMBER, AND MEANS ON SAID CONTAINER ENGAGEABLE BY SAID LOCKING MEANS ON SAID HOOK PORITON MOVES UPWARDLY. 